HYDROIDS OF THE WOODS HOLE REGION. 
383 
rounded by extensively frilled or fimbriated mouth-arms. Radial canals and ovaries exceedingly 
numerous, the latter extending almost to the margin. Size very large. 
Golcrs . — Not given by the original describer. 
I have not seen this species, and condense the description from that of Dr. A. Agassiz. 
Rhegmatodes tenuis A. Ag. Fig. 105. 
(North American Acalephse, p. 95. ) 
Bell very shallow, disk-shaped, with a central elevated portion. 
Tentacles very numerous, slender. Otocysts numerous, situated between 
the tentacle bases. There is practically no proboscis, but an irregular 
aperture under the center of the bell surrounded by an irregularly 
striated membrane which forms the floor of the digestive cavity. 
Radial canals numerous, there being about 32 in specimen examined. 
Ovaries linear, numerous, reaching along the radial canals from the 
digestive cavity nearly to the margin of the bell. 
Colors . — There is very little coloration about this species. The 
ovaries are pale yellowish or brownish. 
Distribution . — Naushon (A. Agassiz). Woods Hole. 
